Hi,

I have a Swisher Zero Turn Lawn Mower bought in 2007. Last Friday I mowed my lawn and at the end of mowing, blow the grass debris from the mowing deck to clean while engine was still running. All of sudden I started hearing noise and strong viration, but could not figure out where was it coming from? I turned off the engin and started again. The sound was still there. Third time, I was not able to start the engine. I tested the original starter by connecting directly to the starter motor, it did not start. In fact flywheel did not move at all. Tried to move flywheel with hand, very hard. My battery is new and replaced the starter with a new one. It still does not start. Any suggestion.

Sounds like a seized piston, main or rod bearing. If it's that hard to turn, time for a teardown.

. Check the engine's oil level. I would only use 10W-30 full synthetic engine oil (e.g. Mobil 1 or Pennzoil Platinum).

. Remove the spark plug from the engine.

. Rotate the flywheel, using a 1/2" breaker bar and socket. Ensure everything rotates properly. If not, the engine needs to be torn down, examined, and rebuilt.

Depending on the engine's make, consider removing the head and scraping all carbon from the top of the piston, head, and valves. This should be done every 100 to 300 hours of operation. Clean carbon build-up around the exhaust port.

. Clean or replace the air filter.

. Clean the cooling fins (head and flywheel) with a brush and compressed air.

. Squirt starter fluid into the cylinder.

. Install a new properly gapped spark plug (usually .030 inch).

. Try to start the engine.

. Scrape old grass from the underside of the mower's deck.